This invention relates to a transfer system for plastic processing machines, which is used to transfer a workpiece to a plurality of processing stations in sequential order, the stations being provided so as to be spaced in the workpiece-transferring direction in such a manner that lower and upper molds for processing the workpiece plastically in cooperation with each other can be set in each of the stations.
In a conventional transfer system of this kind, a workpiece-retainable handling arm is fixed to transfer bars provided at one or both sides of each processing station. The workpiece is transferred by utilizing a combination of the vertical and horizontal movements of the transfer bars.
However, in a prior art transfer system of this kind, the vertical and horizontal movements of a transfer bar are made by a single driving means, so that the amount of driving energy in use necessarily becomes large.
In view of the above facts, the present assignee already proposed (Japanese Patent Application No. 8097/1984) a transfer system in which the vertical and horizontal movements of a transfer bar are made by different driving means. In this proposed invention, the transfer bar as a whole is also driven, and, therefore, the transfer bar is required to be rigid. Moreover, since the dimensions of a plastic processing machine have increased, the dimensions of the driving means must also be increased. This causes an increase not only in the cost of equipment but also in the dimensions of a space in which the driving means is installed.